This invention relates to improved hollow fiber artificial kidneys or hemodialyzers and to a method for the manufacture thereof.
Intermittent dialysis of patients having acute or chronic renal failure has greatly increased in recent years. Flat plate and coil type dialyzers have been replaced, increasingly, by hollow fiber dialyzers of the type disclosed in De Wall U.S. Pat. No. 2,972,349 and Mahon U.S. Pat. No. 3,228,876 and available commercially from Cordis Dow Corporation. Such hollow fiber dialyzers contain thousands of small diameter hollow fibers which are typically cellulose and the product of the cuproammonium process or the process of Lipps U.S. Pat. No. 3,546,209. These fibers are mounted within a tubular dialysis chamber, have a length less than about ten inches and their open ends terminate in spaced apart blood chambers that are formed by headers which are secured to each end of the dialysis chamber by internally threaded caps. The manufacture of such hollow fiber artificial kidneys is difficult and undesirably expensive because of the complexities inherent in the fabrication of the separate components and their subsequent assembly into composite kidney form. Because sterility for all surfaces which contact the blood while it is outside the body during dialysis is an absolute necessity, and it is difficult to sterilize a used artifical kidney for possible re-use, most artifical kidneys are used only once and discarded. Cheaper artificial kidneys are therefore highly desireable.
Those familiar with current commercial systems used in dialysis clinics have criticized conventional use of long blood lines which transport the blood from an artery through racetrack sections to measure blood flow rate, through blood pump tubing, past drip chambers, infusion sites, blood sampling sites and back from the kidney to the patient. Such lines are clumsy to handle, and complicated to assemble, sterilize and maintain. Thus, it has long been recognized that supplemental segments of the extracorporeal circuit, particularly long blood lines, are less than satisfactory and need improvement.
Although current hollow fiber artificial kidneys perform satisfactorily to purify the blood and have developed a good reputation from extensive, successful use in hospital clinics, it is recognized that expert assistance of hospital technicians is needed in connecting the patient to the artificial kidney and associated assisting machines. An improved artificial kidney is still needed that is more easily handled and more easily attached to the patient and to the machine which assists during dialysis in controlling blood flow, dialysate flow and the like.
It has also been recognized as desireable to make an artificial kidney having a single configuration of size and shape but which provides preselected patient-tailored capabilities of rate of water removal and clearances for urea, creatinine, uric acid and other metabolic wastes.
It is therefore a primary object of the invention to provide a hollow fiber artificial kidney that is less expensive to make and more convenient to use than current commercial hollow fiber artifical kidneys.
Another object of this invention is to provide an automated continuous process for making the improved artificial kidneys of this invention.
A further object of this invention is to provide a new hollow fiber bundle adapted to be bonded in a jacket to form a one-piece, integral, non-disassembleable artificial kidney; a related object is to provide the new bundle and jacket portions of such shape, size and arrangement relative to each other that machine handling and bonding of the parts into a unit on a continuous basis is facilitated and human effort required in manufacture is minimized.
A still further objective is to provide an artificial kidney which integrates into a one-piece, integral construction one or more of the necessary supplementary segments of the extracorporeal circuit which are ordinarily separately provided and used during intermittent dialysis such as, for example, blood tubing, drip chambers, blood filters, infusion sites, blood pump tubing, etc.
Another important object is to provide a hollow fiber artificial kidney which minimizes the surface area of foreign material to which blood is exposed while following in the extracorporeal circuit including gases, particularly air, and thereby minimizes the need for anticoagulant.